[tooseevee]

How very interesting. So there’s no valve lash to be set? It’s just built in? Like if the pushrods have no up and down play and rotate by finger than the valves are set to the correct “lash”? Weird.

Well if it’s supposed to be performed cold then mine are too tight, I can’t rotate them at TDC on the compression stroke. I’ll try one more time to get to exact TDc, I might be slightly off TDc, I have to apply so much force even with the decomp lever engaged I kept rolling over TDc. It got to the point I put a rod down the spark plug hole to try and get it as close as I could before it slipped over the top.

            Now I really don't know what to say any more.

            How can you be getting compression pressure if you have the spark plug out?

            With the plug out you can roll the engine over to exactly the place you want it.

[AzCal Retred]

"I thought they should still be able to rotate with the engine cold, no?"

A reasonable person would think so. The overall trend on this valve train appears to be to loosen up as the engine warms, generally a good thing. The game here is to keep the overall thrashing (and shock/impact loading, noise, etc.) to a minimum. 2CV says they should spin freely when cold. This is a safe bet, because other issues that come along with tight (not fully closed) valves don't happen. It's hard to burn a valve seat when the exhaust is actually seated.

Loose valve train clearances can hammer thru protective coatings on cam noses & tappet faces (if any...?), as well as not doing the alloy pushrods & adjusters any favors. IF your machine has a LOT of clatter and shock loads to the valve train, the "warm adjustment" strategy comes into play. A warm adjustment likely means that the valves are likely too tight at start up for the first 30 seconds to a minute, but then come into spec hopefully soon enough to not be an issue. In extreme cases too tight valves can adversely affect starting by not sealing as well and lowering compression.

Start with the "Idiot Proof" methodology of a cold adjustment. After the engine is thoroughly warm, recheck the clearances. For YOUR machine with YOUR components, settle on a methodology that works. If a "free spin" pushrod at cold is still OK when warm or hot, you are done. If it is clattery when warm, find a suitable compromise setting.

My red machine beat thru the tapped disc and cam nose coatings most likely because the valves were too loose too long. These components run in oil, so lube wasn't likely a factor. On the other hand, the valve seats are in good shape. The really good news is that it's only about $300 worth of parts to fix the tappets & cams, and you get to visit their friends the valves when you pull the top end off... It's all a series of reasonable compromises.

These old engines are pretty cool. You can do the normal adjustments whilst on the side of the road anywhere, armed with your fingers, eyes, some tappet wrenches, a plug wrench, a small screwdriver, maybe a bit of cellophane or clean paper to verify contact break and a twig with a pencil mark. Just like the folks that built them rode them every day.

PS - Try using the rear wheel to position the piston at TDC Compression. Machine up on the centerstand, 4th gear, bump the wheel in the normal direction of rotation by hand.

[Blaqkfox]

            Now I really don't know what to say any more.

            How can you be getting compression pressure if you have the spark plug out?

            With the plug out you can roll the engine over to exactly the place you want it.

Well what I did was kick it over till I felt compression, pull the plug, stick a rod down the hole, pull the decomp lever and then ease it up, but it’s still quite difficult, like to the point I have to apply so much force it then rolls over TDc and starts going back down. Not by much, but I can’t seem to get it at exactly TDC. Granted I’m a string bean of a man, and it is quite a lot easier without the spark plug installed, but it’s still difficult. With the plug in it’s extra difficult, it feels like trying to kick over a two stroke with the plug installed. So right now it’s eased up to just slightly before TDC, it’s gotta be super close, probably 5 degrees before TDC or less or so I’d guess, any more and it rolls right over. Is there an easily accessible timing mark I can look at to verify?

[Blaqkfox]

AZcal yeah that’s good, I’ll see what the play looks like when warmed up and try with the rear wheel rotation method.

It’s not really that loud, but it’s louder than any old engine I’ve ever worked on, louder than the sewing machine sound a cb750 makes, or say an old 80s bmw inline 6, basically louder than any rocker arm setup I’ve ever heard. Not by much though, and I hear these like to be noisy, I’m just not used to it so idk what it’s supposed to sound like so I figured I’d check my tappets just for peace of mind. It’s not so loud that I go “there’s a problem here” but it’s loud enough that I go “maybe I should check that to be sure everything’s ok”

And I’m still dealing with the pipes turning blue and all so maybe it’s running hotter than it should so things are getting looser than they should ?

[AzCal Retred]

I think you have an alloy barrel, that'll amplify the valve train noise. When I swapped from the iron barrel to alloy, valve train noise got noticeably louder. The engine is usually around 275F - 325F when running, so the "warm setting" strategy has merit. BUT there has to be enough valve train slop to start & run when cold too. You can see why the move to hydraulic valves was made on the UCEs. The rubber fin plugs likely helped some with noise, maybe...?

An EGT would be a very nice addition, or at least an infrared "heat gun" temp device to quantify exhaust gas temp for tuning. Better & more informative that worrying about low-buck Indian chromium colour. Keep after it!    - ACR -

[Adrian II]

You are trying to get TDC on the COMPRESSION stroke, aren't you? That way both cam lobes should be down and the valves both shut, assuming tappet clearances are within tolerance, therefore no valve spring pressure trying to force things.

The rocker covers are on top of the cylinder head, you wouldn't normally disturb them just for setting the tappet clearance, you just need that rectangular cover at the top of the crankcases off.

A.

[Blaqkfox]

Yes Adrian, on the compression stroke so the valves are closed and there’s no pressure on them. Still can’t rotate them. May just pull the rocker covers to verify since I’m not at exact TDC.

And yeah I have an IR gun, I’m reading around 280-285F on the cylinder head, like 315-ish on the flange for the header, and only about 150F midway down the header where it’s turning blue/purple

[AzCal Retred]

At TDC Compression both the tappets are riding on their cam base circles, maximum clearance. Only way pushrods won't rotate is if they are under compression loading. Loosen them up until they spin free at TDC, then you will know what you got. See what happens as the motor warms up, when/IF they get looser. Adjustment is easy.

IF the clearance is metal to metal, maybe the pushrods & valve springs under compression are imparting their stored energy to the crank, preventing you from getting a stable crank position. Go "loose" until this is sorted.

[Blaqkfox]

Yeah I’ll get it sorted tomorrow evening.

Let me ask y’all this, would it be a big deal if I ride the bike before my upsized pilot jet comes in?

In other words, does the pilot effect much fuel ratio when I’m riding the bike at half throttle and above?

I hear the pilot does still keep working throughout the throttle range but it really doesn’t do much to the air:fuel aside from idle of course.

Cuz I’ve got a 120 main jet now from work I’m going to install, and I’ve got a 17.5 pilot jet on the way, but it’s supposed to be beautiful this week and I want to ride it the 64 miles to work and back. It’s literally a straight shot on country back roads, so it’ll be richened up with the choke to warm up and then I’ll be off and riding half throttle and above the whole way there pretty much.

I mean I’ve done it for 400 mile now with the stock 15 pilot jet and a 118 main jet, so its probably fine, but I don’t wanna run it lean over and over again ya know.

I’ll be ordering a new exhaust tomorrow too and then I’ll have to tune for that I suppose but it seems everyone says to use that 120 and 17.5 setup so I hope that works or I’ll have to put it up and order a full jetting kit. Also how do I keep the new exhaust from discoloring while I tune it?

[AzCal Retred]

Main jet really doesn't do much until around 2/3rds of throttle opening.

Pilot is important up to maybe 1/4th throttle valve open, then the needle/needle jet is the main metering from there to maybe 2/3rds open. Mostly my Bullet is at an easy 1/4th - 1/3rd throttle at 50-55, flat ground, no wind. WOT is maybe for a few seconds getting away from a stop sign and back up to speed. Hills are climbed by downshifting until you find a gear and a speed combo that "runs free", not buzzing, not lugging, just has some reserve power to accelerate a bit if need be. Often on my 4 speed the gearing and available power determine road speed of a climb. You learn to like what you get.

You can screw in the air bleed needle a bit to richen up the off-idle circuit, maybe raise the needle one notch from center. You have the AVL, so you have a "normal" high(er) silicon alloy piston, so it's a lot tougher than the Velveeta ones the Iron Barrel Pre-Unit came with. These long stroke machines like light load and moderate RPM, no buzzing, no lugging. 55 on the road on my 500 Bullet is comfortable, no abnormal thermal or mechanical loads, your AVL is likely the same deal. "55 all day long, 65 for awhile, 80 one time" is a useful mantra. I can't see how you'd hurt it so long as it's "running free" and not being thrashed. Properly jetted it'll run better, but I'm not seeing any unsurmountable obstacles.

"Also how do I keep the new exhaust from discoloring while I tune it?"
Don't sweat the non-important stuff. If chrome cleaner won't make it "purdy" again, there's a universe of Hi-Temp paints out there...
Nobody will ever give you a gift card because your machine didn't show usage, and if you aren't using it...who cares how purdy it is?  A picture would be easier. Go ride & enjoy your 1940 time machine! 

 

[Blaqkfox]

Right so this is where things get interesting, my needle is already on the last (3rd) clip, so the needle is sitting at its highest, which should be the richest setting correct?

Well when it was all stock and the plug looked lean we decided to add two needle shim, effectively moving the needle one notch richer beyond its factory adjustability. The plug started to brown like a proper plug should after one ride around the block.

I long story short I change some things around based on how I rode the bike (I mainly use it at 3/4 throttle or more to cruse at 65mph down highway and curvy country back roads, can’t say I’ve ever heard it buzz but it only lugs if I don’t really gas it taking off in 1st or if I’m under shifting, I’ve had it to 70-75mph a few times, the previous owner mentioned he hit 86mph on it once. This AVL seems to cruise happily at 65mph). And after upsizing the main jet the bike feels like it bogs more than it should midrange and at wot, so I end up removing the shim on the needle and the midrange feels like it has more get-up-and-go now but wot still feels like it’s maybe got some bog to it, maybe not bog, not like when you’re trying to come out of 1st with not enough throttle and it’s lugging along, no, it’s more just like it feels it should have more acceleration to it than it does. So that’s got me thinking it’s actually too rich on the main jet. Or it’s just this bikes always run too lean. I can’t decide. 

Thing is, i know removing the needle shim helped just because lean=power but am I too lean? Moreover, does changing the main jet have any effect on the needle too? In other words, if I change my main jet will it effect my air:fuel midrange since the needle and main jet sorta work together? I mean I know the needles for mid range and the main jet is for more wot controls, but people always talk about re-jetting but hardly ever mention changing needle position in junction with a larger main jet, so do I need to do both or will just installing the larger main jet do the trick alone?

[Paul W]

To set the clearance, you’re trying to find the place where both cam followers are on the base circles of the cams, which occurs at TDC, plus a few degrees either side.

If the spark plug is in place, the engine certainly isn’t going to stay at TDC because compression will force the piston over. Using a rod in the spark plug hole is a recognised technique, so it’s not unusual to do that.

When checking the clearances are “nil” at cold I rotate the engine on the kickstarter whilst trying to rotate the pushrod with the end of my index finger. With this method, if there is any undue up/down clearance, you feel it come and go.

The clearances on Bullet engines get wider as they warm up, btw, which is why they’re set at cold.

[tooseevee]

You can screw in the air bleed needle a bit to richen up the off-idle circuit, maybe raise the needle one notch from center.

           I believe you'll find the mixture screw on the UCAL BS 29 CV carb is a fuel screw not an air screw. Screwing it in (CW) leans the mixture.

[AzCal Retred]

Good call 2CV!

2004-2008%20500cc%20Electra%20X.pdf ; Page 08-4:
Air-fuel mixture is adjusted by pilot screw (PS) and mixture becomes lean when PS is tightened (PS turned clockwise) and rich when it is loosened (PS turned anticlockwise).

[Blaqkfox]

yeah 2CV is correct on that.

I just posted in another thread but ill update this one too I guess since were talking about the same thing in here now...

So today I switched to a 17.5 pilot jet and a 120 main jet. To recap all I've done is delete the baffle in the header pipe.

The bike was hard to start until I found the right fuel screw setting of course.

I dialed things in, I found it was much easier to tune with the idle set pretty high, I could actually hear the revs increase then. And once it was in the right area I let it idle down and then I could distinguish the rev increase and decrease finally.

I too rich now though...





Granted I am about to buy a different exhaust since this one is all blue now. How do you tune it in without turning the new exhaust blue?

I think I like the sound of the Goldstar that H's sells the best. I might need a high flow K&N too yeah? I guess well see if it leans out a little with a less restrictive silencer in the mix next.

ALSO to add to this, I did check my tappets once warm.

I could now rotate the intake push rod once the bike was up to operating temp- around 280F, and it did have about 1mm of up and down play. Should I tighten it or leave it alone?

I could not rotate it when cold.

As for the exhaust pushrod... I could not rotate it when cold either, and even once warm it either wouldn't rotate at all or was very hard to rotate, with no up and down play. So maybe I should loosen that one? IDK it was hard to get a finger on it for the decompression release collar in the way...

actually come to think... I didn't put the darn thing at TDC so all this is bogus info... well crap... ill have to redo this...